Dialysis to support a patient whose renal function is inadequate is well known. Two principal dialysis methods are utilized: hemodialysis or “HD”, and peritoneal dialysis or “PD.”
Hemodialysis is carried out by passing the patient's blood through a usually external dialysis machine typically in a clinical setting. A hemodialysis (HD) machine contains a dialyzer with a semi-permeable membrane that allows water and waste products to pass out of the blood into a dialysate solution. The HD machine thus acts as an artificial kidney for cleansing the blood. The diffusion of water and solutes across the membrane during hemodialysis is called ultrafiltration.
Peritoneal dialysis (PD) utilizes the patient's own peritoneum, a membranous lining of the abdominal body cavity. With its good perfusion properties, the peritoneum is capable of acting as a natural semi-permeable membrane for transferring water and waste products to a type of dialysate solution known as PD solution introduced temporarily into the patient's abdominal cavity. An access port is implanted in the patient's abdomen and the PD solution is infused usually by a pump into the patient's abdomen through a patient line and left to dwell for a period of time and then drained out. This procedure is usually repeated several times for a complete treatment.
PD machines called cyclers are designed to automatically control the filling, dwelling, and draining of PD solution to and from the patient's peritoneal cavity. A PD cycler is an attractive solution for many kidney patients because it can be used at home while the patient is asleep, avoids extracorporeal blood transit, and lessens the need for visits to the clinic for hemodialysis.
A PD treatment typically lasts for several hours, and often begins with an initial drain cycle to empty the peritoneal cavity of spent dialysate. The sequence then proceeds through a succession of fill, dwell, and drain phases that follow one after the other. A PD machine can be programmed by the patient according to the doctor's prescription guidelines to vary the fill, dwell and drain times, total time and volume of fluid transferred. These are settable parameters on the PD machine's graphical user interface, usually including, e.g., a touch screen and/or keypad and control buttons.
The PD solution itself is usually sourced from a set of pre-filled bags which are connected via tubing to the machine for warming and pumping PD solution through the patient line. The machine itself includes a console with a computer and pumps and valves controlled by the computer to pull PD solution from the correct bag and pump it to the patient, and then, after a programmed interval, draw fluid out of the patient to a drain or drain bag. The fluid lines may include a removable flexible plastic cassette with pump chambers, valve elements and channels connected to the patient and drain lines and PD solution bags via tubing, as shown, for example, in pending U.S. Published Patent Applications US 2006-0195064 A1, published Aug. 31, 2006 and entitled “Portable Apparatus for Peritoneal Dialysis Therapy,” and US-2007-0112297-A1, published May 17, 2007 and entitled “Cassette System for Peritoneal Dialysis Machine,” both of which are incorporated herein by reference in their entirety. The cassette may be inserted into a pressurized door where it mates with the pumping mechanism and valve actuators. The cassette and its associated tubing are for one time use and are disposable after each dialysis session.
To set up a PD treatment, the patient or someone assisting the patient must generally do two things: physical set up and programming. Physical set up may involve, e.g., arranging and powering up the PD machine console on a table, for example, next to a bed where the patient will be lying, obtaining the PD solution bags and a fresh set of disposables (e.g., cassette and tubing), installing the bags and disposables correctly on the PD machine and connecting the patient line to the patient's abdominal access port. The programming part of the set up may involve, e.g., selecting the mode of operation and setting the aforementioned parameters via the PD machine's user interface, which may include a touch screen, or a combination of touch screen and keys (e.g., feathertouch keys) or buttons.
These tasks generally take a certain amount of training on any PD machine in order to correctly set up and carry out the procedure.
Likewise, to set up an HD treatment, a patient (or someone assisting the patient) must generally go through a series of steps to physically set up and program an HD machine. These tasks likewise generally take a certain amount of training on the HD machine.